1. Field of Invention
This invention pertains to mechanisms for positioning the body attitude or inclination in a desk chair of the type used in offices.
2. Description of the Prior Art
Desk chairs used in offices are designed so that they can rotate or swivel about a vertical axis and tilt about a horizontal axis. Such chairs usually comprise a base resting on the floor, a chair frame including a seat, a backrest, lateral arm rests and a mechanism which permits the frame to rotate with respect to the base in two different planes as indicated above. The prior art mechanisms utilize rather complicated designs and are relatively expensive to make. Furthermore, the horizontal axis around which the frame typically tilts in the prior art mechanism is usually located far from the front edge of the seat so that during the tilting motion the front edge of the seat rotates severely upward. It was found that this type of motion is undesirable because it can interfere with the blood circulation in the legs of the person using the chair, causing muscle fatigue and other similar discomforts.
In addition existing desk chairs are uncomfortable because they do not follow all the body movement of the occupant, and do not support the body especially when the occupant leans forward toward a working position.
Furthermore, it is well-known that different tasks require different body positions. For example, certain tasks, such as typing, using a word processor, a microcomputer or a telecommunication terminal require a forward tilting position. Other tasks such as reading, or talking on a telephone prefer a backward leaning position. However, the prior art chairs presently available are adequate at most for only one of these positions.